Adjustable latch bar mechanism



Feb 27 1951 P. v. LARSEN ADJUSTABLE LATCH BAR MECHANISM Filed Aug. 2, 1949 5 Sheets-Sheet l INVENTOR. Paal' Z7. arse/fa Feb. 27, 1951 P. v. LARsl-:N

ADJUSTABLE LATCH BAR MECHANISM 5 Sheets-Sheet 2 Filed Aug. 2, 1949 m Mw vC. m WwW, Ha@ M .D1

Feb. 27'9 R951 P. v. LARsEN ADJUSTABLE LATCH BAR MECHANISM 5 Sheets-Sheet 3 Filed Aug. 2, 1949 JNVENToR. pa LZ U arse/z BYMQf-Cz.

Patented Feb. 27, 1951 ADJUSTABLE LATCH BAR MECHANISIVI Paul V. Larsen, Portland, Oreg., assigner to Electric Steel Foundry, Portland, Oreg.,

tion of Oregon Application August 2, 1949, Serial No. 108,082

4 Claims. (Cl. 292-186) This invention relates to an adjustable latch bar mechanism which is suited to use on power shovel dipper doors and the like, and particularly where the latch bar is subject to wear in use.

One of the objects of my invention is to provide a latch bar mechanism in which adjustments may be made in a series of relatively small increments to compensate for wear on the latching end of the latch bar, and which provides a wide total range of adjustments, even though the increments may be small.

As another object, my invention has within its purview the provision of an adjustable latch mechanism of the character referred to and which is constructed and mounted in a manner such that distortion and bending of the door upon which it is mounted do not prevent the operation thereof.

My invention further comprehends an adjustable latch mechanism of the type referred to and which embodies parts reversible for either right or left hand operation.

Other objects and advantages of the invention will be apparent from the following description and the accompanying drawings, in

` which similar characters of reference indicate similar parts throughout the several views.

Referring to the drawings, of which there are three sheets,

Fig. 1 is a side elevational View of a shovel adapted to power operation and of a type utilizing a dipper door upon which my adjustable latch mechanism is suited to use;

Fig. 2 is an elevational view of a dipper door of the type depicted from the side in Fig. 1 and having a preferred embodiment of my adjustable latch mechanism mounted thereon;

Fig. 3 is a View similar to Fig. 2, but drawn to a larger scale and showing the parts of my adjustable latch mechanism in the positions normally assumed with a new latch bar;

Fig. 4 is a fragmentary View similar to Fig. 3, but illustrating the relative positions of the parts after some adjustments have been made to compensate for wear on the end of the latch bar;

Fig. 5 is a fragmentary view' similar to Fig. 4, but showing an extreme position of adjustment reached after the end of the latch bar has been worn away practically to the limit of its usefulness;

- Fig. 6 is a fragmentary sectional view wherein the section is taken substantially on a line 6-5 of Fig. 4 and in the direction indicated by the accompanying arrows;

Fig. 7 is a fragmentary sectional view taken substantially on a line 'l-l of Fig. 3 and in the direction indicated by arrows; and

Fig. 8 is a fragmentary sectional view wherein the section is taken substantially on a line 8-8 of Fig. 4 and in the direction indicated by arrows.

Having reference to the drawings wherein an exemplary embodiment of my invention is depicted for illustrative purposes, Fig. l shows a side view of a shovel it normally carried for power operation by a dipper arm I2; the shovel being provided with digging teeth I3 which project from a wall thereof adjacent an open side. A door i4 is supported for swinging movement relative to a hinge axis l5 by hinge bars V5 and El'. As shown in Figs. 2 and 3, the hinge bars extend along and are secured to a main door plate i3 at opposite sides thereof and in substantially parallel relationship to one another. Laterally, the door is braced by a substantially rigid cross member li) at the mid-portion of the door and secured to both the main door plate and the hinge bars. A second substantially rigid cross member 2li extends across the door in substantially parallel relationship to the cross member I9 and near the edge of the door which is op-l posite the axis of swinging movement thereof. The lateral cross member is also secured to both the main door plate and the hinge bars.

Midway between their opposite ends, the cross members l5 and 20 are provided with aligned bearings 22 and 23 respectively having bearing openings 213 and 25 therethrough in which a latch bar 25 is mounted for longitudinal sliding movement between latching and retracted positions. in Fig. 3, a latch tongue 2l which comprises one end of the latch bar projects beyond the edge of the door and is shown in its normally extended or latching position in solid lines; the retracted position of the end of the latch tongue being indicated in dotted lines at 28. Near the end of the latch bar opposite the projecting latch tongue, longitudinally elongated slots 29 and 3i! are provided in the latch bar at positions spaced longitudinally of that bar.

In use, latch bars of the type disclosed wear off at their projecting or latching ends, thus 'making it necessary to provide an adjustment of the position of the latch bars which compensates for the wearing away of the one end. In the disclosed structure, I have provided an adjustable actuating mechanism for the latch bar which provides a long range of ultimate adjustment with small increments of successive steps of adjustment intervening between the ultimate limits.

This adjustable latch actuating mechanism includes a latch lever support 32 having a circular opening 33 at one end thereof with a series of equally spaced and similar teeth 34 projecting inwardly in a radial direction around the periphery of the opening. An eccentric 35 has peripheral teeth 35 and nts into the opening 33 in a plurality of positions withv the teeth thereof meshing with those on the periphery of the opening 33. A shaft 3'! extends through the eccentric 35 with its axis displaced radially from the geometric center of the eccentric.

On opposite sides of the latch 26, similar slots 33 and 39 are provided in longitudinal reinforcing ribs 49 and 42 which extend from opposite sides of the bearing 22, either of which slots is adapted to accommodate the end of the latch lever support 32 with the eccentric 35 mounted therein. At the mid-portion of the slots Z9, bores 43 and 44 extend through the cross member I9 in parallel relationship to one another` and in directions transverse to the slot with their axes spaced from one another in a direction parallel to the longitudinal axis of the latch bar.

It may be observed that when the position of the eccentric 35 is circumferentially shifted with reference to the latch lever support 32 from the position shown in Fig. 3, the position of the latch lever support is shifted longitudinaly of the latch bar. The teeth on the eccentric and latch lever support determine increments of adjustment; the limit of adjustment by relative movement of the eccentric with respect to the latch lever support being 180 degrees of movement of the eccentric. Upon reaching such limit, the shaft is shifted from the bore 45 to the bore 46 and the eccentric is returned to its initial position relative to the latch lever support. Preferably, the spacing between the bores 45 and 46 is approximately twice the displacement of the axis of the shaft 3T from the geometric center of the eccentric, so that the adjustment accomplished by movements of the eccentric continues after movement of the shaft.

As shown in Fig. '7, the end of the latch lever support 32 opposite the eccentric 35 is provided with a bearing bore 48, the axis of which is substantially parallel to the axis of the shaft 3l. A latch actuating lever 49 has a bifurcated end 59 which is provided with a bearing bore 52 and which is movably connected to the latch lever support by a shaft 53 which extends through the bearing bores 48 and 52 and is secured in place by fastening means such as a cross bolt 54.

At a position near the bearing bore 52 in the bifurcated end of the latch lever, a second bearing bore 55 extends therethrough and has a shaft 56 mounted therein and secured in place by fastening means such as a cross bolt l. The latter shaft extends through a selected one of the slots 29 or 30, to provide an actuating connection between the latch lever 49 and the latch bar 26; the latch lever support 32 and the shaft 53 providing a fulcrum for swinging movement of the latch lever between positions such as those indicated in solid lines at 49 and dot and dash lines at 49a in Fig. 3, whereby to effect linear movement of the latch bar between its latching and retracted positions.

A guide bar 58 has a longitudinal slot 59 therein through which the latch lever 49 extends, and is located on the side of the latch opposite the latch lever support; the ends of the slot 59 serving as stops to limit the movements of the latch lever. One end of the guide bar 58 is secured to the main door plate I8 by fastening means such as a rivet 60, while the other end has a projecting lug 02 thereon which extends into a selected one of the slots 38 or 39 depending upon whether the latch lever is to be operated from the left or right side of the latch bar. In the disclosed structure, a shaft 63 extends through the bore 43 and is held in place by fastening means, such as a bolt 64, to hold the guide bar in place with respect to the cross member I9.

From the foregoing description, and reference to the accompanying drawings, it may be understood that when a new latch bar is installed, and parts are assembled in the positions and relations depicted in Fig. 3; such positions providing for a maximum range of adjustment to compensate for wearing away' of the latch tongue 2l at the end of the latch bar. As wear progresses, the eccentric is shifted in position rotationally with respect to the latch lever support 32 in successive increments and until it reaches a position substantially as illustrated in Fig. 5. From that position of adjustment, the eccentric is returned to its initial position and the shaft 3l' is moved from the bore 45 to the bore 46, from which position the Series of incremental adjustments is repeated by rotational movement of the eccentric with respect to the latch lever support 32. Subsequently, and to compensate for further wear of the same latch bar, the shaft 37 and eccentric S4 are moved to their initial positions, with the shaft 3l in the bore 45, and the shaft 56 is moved from the slot 3U in the latch bore to the slot 29. With the latter connection between the latch lever and latch bar, the full series of incremental movements may be again effected by shifting the eccentric, as well as the shaft 3l. This arrangement of parts provides a very wide range of the total movement which may be effected to compensate for wear of the latch bar, while providing definite, successive and small increments of adjustment between the ultimate limits.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

1. An adjustable dipper door latch mechanism comprising, in combination, a substantially rigid support member secured to the door and having a latch bar bearing therein, a latch bar linearly movable in said bearing between latching and retracted positions, a latch lever support having a circular opening at one end thereof with radially disposed teeth projecting inwardly from the periphery of the opening, said latch lever support having a bearing bore at the other end thereof, a gear-type eccentric having a toothed periphY ery fitting into said opening at any one of-a plurality of positions, means for supporting said eccentric for rotation relative to said rigid support member and about an axis displaced from the geometric center of the eccentric, whereby changing the position of the eccentric relative to the latch lever support varies the position of the latch lever support longitudinally of the latch bar and relative to the rigid support member, a latch actuating lever, means for connecting one end of the latch actuating lever vto said other end of the latch lever support for vswinging movement about the axis of said bearing bore, and means for connecting the latch actuating lever to the latch bar, so that swinging movement of the latch actuating member eiects longitudinal movement of the latch bar.

2. An adjustable dipper door latch mechanism as defined in claim 1, and wherein said means for supporting the eccentric includes a shaft providing said axis displaced from the geometric axis of the eccentric, and said rigid Support member having bores therein displaced from one another longitudinally of the latch bar for selectively receiving the shaft to provide a second adjustment of the position of the latch lever support longitudinally of the latch bar, said bores having their centers displaced approximately twice the distance of the displacement of the axis of rotational movement of the eccentric from the geometric center thereof.

3. An adjustable dipper door latch mechanism as dened in claim l, and wherein said means REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Larsen Apr. 17, 1945 Number 

